The present invention relates to a physiological magnetic field measuring instrument for measuring the magnetic field of a living body generated due to the internal current relating to the cerebral nerve activity and myocardial activity of a living body.
Conventionally, a multi-channel (many magnetic sensors arranged in a matrix) physiological magnetic field measuring instrument using a superconducting quantum interference device, which is a magnetic sensor for measuring a minute magnetic distribution generated from a living body inferring the active current position in the living body, and imaging the distribution is well known.
A conventional example such as a magnetometer or gradiometer is disclosed, for example, in Japanese Patent Application Laid-Open 4-319334, Japanese Patent Application Laid-Open 5-146416, and Japanese Patent Application Laid-Open 10-5186.
This kind of physiological magnetic field measuring instrument is being put into practical use and as a condition necessary for practical use, it is desired to detect a minute magnetic field generated from a living body by removing the effect of noise as much as possible. For that purpose, to remove the effect of environmental magnetic noise, a magnetic field measuring instrument is installed inside a magnetic shield room or for example, the following measuring signal process is known.
For example, the physiological magnetic field measuring instrument described in Japanese Patent Application Laid-Open 10-5186 indicates an example of measurement of the magnetic field generated from the brain, and proposes a fluxmeter (composed of a plurality of magnetic sensors) for measuring a minute magnetic field generated from a patient, and an electrocardiograph for measuring an electrocardiac waveform of the patient. A match of the magnetic data measured by the fluxmeter with the cardiac data measured by the electrocardiograph is obtained, and when the match of the two is high, the magnetic data is handled as defective data, but when the match is low, it is retained as one which is not affected by noise. These operations are performed repeatedly, and after termination of the predetermined count, the retained physiological magnetic field measured data is added and averaged in data collection units.
The aforementioned prior art is one relating to the operation principle concerning a physiological magnetic imaging device and the description does not include technical problems and solving means for practical realization. The aforementioned prior art relates to the physiological active current generated inside the brain but does not include concrete description concerning other parts.
Furthermore, the aforementioned prior art is attempted, when performing an averaging process for cerebral magnetic data using the physiological magnetic field measuring instrument (cerebral magnetic meter), to remove the noise synchronized with the heart beat simultaneously using the electrocardiograph, but it neither considers a case that the physiological magnetic field measuring instrument is used for a magnetocardiograph meter nor intends to independently use the physiological magnetic field measuring instrument.
An object of the present invention is to provide a physiological magnetic measuring method and a physiological magnetic field measuring instrument so that the magnitude of magnetic field at a plurality of measuring positions can be measured easily and satisfactorily.
Another object of the present invention is to provide a physiological magnetic field measuring instrument realizing highly reliable automatic average processing by automatically selecting good or defective data by magnetocardiograph measurement or cerebral magnetic measurement independently, using the physiological magnetic field measuring instrument without simultaneously using the electrocardiograph.
Still another object of the present invention is to provide a method, when there is sudden abnormal data in measured data as a result of physiological magnetic field measurement, for automatically selecting and displaying it and using the abnormal data as information useful for diagnosis.
Furthermore, the present invention contributes to integrated automation from reading of measured data (signal waveform) of the physiological magnetic field measuring instrument to data analysis, and simply executes operation and condition setting.
According to the present invention, a method for measuring the magnetic field generated from the inside of the living body of a patient at a plurality of positions has a means for displaying a plurality of measuring positions on the display screen, a means for selecting the position to be displayed from the displayed measuring positions, and a means for displaying information concerning the magnitude of magnetic field at the selected position, and displays the plurality of measuring positions together with the existence of selection in the display state that the information concerning the magnitude of magnetic field is displayed. The present invention provides the channel item corresponding to the channel displayed on the analytical data display unit in the operation area display unit. The present invention also provides the other measuring items.
According to the present invention, the physiological magnetic field measuring instrument for measuring the magnetic field generated from the inside of the living body of a patient has a waveform recognition means for recognizing characteristic waveforms repeatedly appearing by physiological activity from the measured signal waveforms, a reference waveform registration means for registering one of the characteristic waveforms repeatedly appearing as a reference waveform, a waveform evaluation means for evaluating the difference degree of each of the characteristic waveforms repeatedly appearing from the reference waveform, and a calculation means for executing the averaging process using only the waveforms whose difference degrees are less than the allowable value.
By use of such a constitution, from actually measured signal waveforms of each person, the reference waveform is set. Such a method provides the following advantages. Namely, since there is an individual difference in the state of the characteristic waveform (for example, heartbeat waveform) repeated by physiological activity, when the reference waveform is identified from signal waveforms repeated by true physiological activity of each person like the system of the present invention, a reference waveform actually suited to each person can be set better than when the reference waveform is temporarily set from the standard simulated waveform.
As a method for identifying the reference waveform of the present invention, for example, a method for registering the n-th waveform (for example, the first waveform) from the waveform recognized by the waveform recognition means as a reference waveform may be considered. When the identified reference waveform is accidentally sudden defective data, waveform data having a difference degree less than the allowable value cannot be read by the predetermined count. If this occurs, when the reference waveform identifying operation is performed until waveform data suited to the reference waveform can be identified by reexecuting registration of the reference waveform and evaluation of the difference degree in the same way as with the previous one after remeasurement or newly selecting the aforementioned reference waveform and reexecuting the averaging process, the above problem can be solved.